The present invention relates to shampoo compositions, and more particularly to shampoo compositions containing non-volatile silicone materials which condition the hair leaving it softer and more manageable.
When washing the hair with conventional shampoo compositions, the natural oils are removed together with the dirt and unwanted oils. When too much of the natural oil is removed, for example by especially frequent washing, the hair becomes less easy to comb or style, and subject to static build-up causing "flyaway".
Hair conditioners have been developed to try to restore the condition of the hair. These compositions are normally applied to hair after shampooing, left on the hair for a period of time and rinsed off. This process is time consuming and expensive since two separate products are needed.
Conditioning shampoos containing cationic conditioning agents have been disclosed for example in EP 18 717 (Unilever). These cationic agents confer some conditioning benefit on the hair, but are often thought to leave a residue on the hair, which may cause dulling on hair after drying.
Non-volatile silicone oils are useful as conditioning agents, but again excessive amounts of silicone can dull the hair, and build-up of silicone on the hair can give a greasy appearance. Furthermore, the incorporation of silicone oil generally gives an antifoam effect.
Hair conditioning emulsions are disclosed in EP 35 899 (Proctor & Gamble). These emulsions comprise volatile silicone or volatile hydrocarbon, and the particle size of the volatile material in the final composition is said to be from 1 to 10 .mu.m.
However, such compositions are not suitable for use as shampoos, and the hair should first be washed before applying the conditioner emulsion.
Non-volatile silicone oil has been incorporated directly into shampoo compositions, as disclosed in EP 74 264 (Unilever), however the silicone oil is incorporated directly into the compositions, giving a particle size larger than 2 .mu.m, and an antifoam effect can be seen.
We have found that the combination of an aqueous emulsion of a silicone oil with a particular type of cationic conditioning polymer in a surfactant-based shampoo composition will impart improved conditioning benefit to the hair with none of the undesirable dulling effects or greasy build-up seen with other conditioning products, and without the need for a two-step washing and conditioning procedure.
Incorporating the silicone oil as a preformed aqueous emulsion has the consequences that the silicone is incorporated with a small particle size, less than 2 .mu.m. The silicone is insoluble and remains emulsified in the overall composition. Incorporating the silicone oil in this way makes the manufacture of the compositions easier. It also reduces the antifoam action of the silicone oil and leads to compositions of greater stability.
Accordingly, the invention provides an aqueous shampoo composition comprising, in addition to water
(a) from 2 to 40% by weight of surfactant chosen from anionic, nonionic or amphoteric surfactants or mixtures thereof; PA0 (b) from 0.01 to 3% by weight of cationic conditioning polymer which is a cationic derivative of guar gum; PA0 (c) from 0.01 to 10% by weight of an insoluble, non-volatile silicone, present as emulsified particles with an average particle size of less than 2 .mu.m.
In another aspect, this invention provides a method of making such a shampoo composition, by mixing together water, the surfactant, the cationic conditioning polymer and an aqueous emulsion of the silicone, wherein the silicone in the emulsion has an average particle size of less than 2 .mu.m.